The surface of tires supports a large quantity of markings intended on the one hand to provide technical information as to the quality of the tire, and on the other hand to allow the consumer to discern the make and origin of the product. As a general rule, these markings are obtained by raised patterns arranged on the surface of the tire and corresponding to recessed patterns made on the moulding surface. Vulcanizing moulds are usually made of metal with a very good surface-finish but the resulting, smooth and black external surface of the tire has the effect of reflecting light.
Document WO2007/045425 describes particular types of high-contrast texture on tires. These textures have the main effect of trapping incident light and, by absorbing light, of giving part of the tire a black and matt appearance. This absorption of light makes it possible to obtain a more intense black colour that forms a better contrast with the rest of the surface of the tire. The contrast is all the greater when the texture sits alongside bright surfaces on the tire.
The contrast obtained by this absorption of light produces an appreciable visual effect on the finish of the product, often likened to the visual appearance of velours. Now, obtaining textures that produce such an effect is still at the present time a technological challenge that has been resolved only in part. Specifically, the current methods are relatively expensive and tricky to implement, and only allow the production of certain types of pattern, at certain locations, generally those that are easy to access.
Patent application WO 2010/076502 proposes a lining assembly for a tire mould comprising a skin. The skin is delimited by a first and a second surface that are opposite surfaces, the first surface being intended to be in contact with a tire mould support block and a plurality of lining elements projecting from the second surface of the skin, these elements being intended to form tread patterns in part of a radially external surface of a tire. Such an assembly makes it possible to obtain conventional tread patterns such as those of the treads of conventional tires.
Application WO2014060209 describes a moulding element for a tire mould manufactured from a metallic powder which is melted layer by layer. This moulding element comprises a first surface intended to mould all or part of a tire tread surface, and a second surface, on the opposite side to the first surface, and intended to be in contact with another part of the mould. The thickness of the moulding element is comprised between 1 and 6 millimetres. The moulding element has an overall density greater than or equal to 98%. The moulding element further comprises at least a first porous region extending into the thickness of the said mould element. The first porous region comprises a plurality of pores allowing air to pass between the first surface of the moulding element and the second surface thereof.
There is at the present time a need for solutions that make it possible to produce tires provided with intense black textures with great flexibility and advantageous costs.
In order to alleviate these various disadvantages, the invention provides various technical means.